Keysight Technologies L4445A Configuration manual

Brand: Keysight Technologies

Model: L4445A

Type: Configuration manual

Keysight Technologies

34945A, L4445A, and L4490A/L4491A

Configuration Guide

RF/Microwave switches are used in a wide variety of applications ranging from DC to over

50 GHz. These applications can include:

– Wireless Communications

– Broadband CATV

– Communication Satellites

– Test and Measurement Equipment

– Electronic Radar and Defense Systems

– Avionics

– Medical Electronics

– Space Programs.

High Frequency measurement systems can be configured to route RF/Microwave signals in a

variety of configurations including:

– Selection from multiple signal sources to a single output

– Selection of multiple input signals to a single measurement instrument

– Transfer switching to insert or remove a device in a signal path

– Matrix switching of multiple inputs and outputs

Keysight Technologies, Inc. is a leader in providing RF/Microwave switching solutions. Keysight’s

solutions include both RF/Microwave switch modules and switch driver instruments that control

discreet (external) switches and attenuators physically located at the site of the device under

test (DUT) or application.

The purpose of this configuration guide is to introduce you to the features of the Keysight

34945A, L4445A, and L4490A/L4491A family of RF/Microwave switching instruments, and to

assist you in the three step process of selecting and configuring your Keysight system:

Step 1: Select the switches/attenuators and their options for your application.

Step 2: Determine the type and number of distribution boards required, and the bracket and

cable kits required.

Step 3: Select the switch driver instrument or switch platform you plan to use.

Introduction

Step 1

Table 1. Common Keysight RF/Microwave Switches and Attenuators

Switch

model Description

Frequency

range

Reference

document

number 1

Coil

voltage

option

Position

indicator

option

connector

option

Distribution board

[number of

switches/board]

Bracket kit 3

(Cable kit) 3

N1810UL

N1810TL

N1811TL

N1812UL

Un-terminated latching 3-port

(SPDT)

Terminated latching 3-port (SPDT)

Terminated latching 4-port

(bypass)

Un-terminated latching 5-port

DC – 2, 4, 20,

or 26.5 GHz

5968-9653E

124 402/403 2201

(DB9F)

Y1150A [8]

Y1152A [2]

Y1154A [6]

Y1170A: L4491A

Y1171A: L4490A

(Y1157A)

87104A

87104B

87104C

87106A

87106B

87106C

87106P

87106Q

87106R

87406B

87406Q

SP4T 4-port latching, terminated

SP6T 6-port latching, terminated

Low PIM Switch, SP6T 6-port,

latching, terminated

Low PIM Switch, SP6T 6-port,

latching, terminated

Low PIM Switch, SP6T 6-port,

latching, terminated

6-port matrix, terminated

Low PIM Switch, 6-port matrix,

terminated

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC - 4 GHz

DC - 20 GHz

DC - 26.5 GHz

DC – 20 GHz

5091-3366E

87104-80017

5965-7841E

87406-80005

024: 24 VDC

T24: TTL/5 V

CMOS

compatible

Included 161

(16-pin DIP) Y1151A [2] Y1172A

(Y1159A)

87204A

87204B

87204C

87206A

87206B

87206C

87606B

87606Q

SP4T 4-port latching, terminated

SP6T 6-port latching, terminated

6-port matrix, terminated

Low PIM Switch, 6-port matrix,

terminated

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 20 GHz

5965-3309E

5965-7842E

87606-80005

Included

024: 24 VDC

Included

N/A

161

(16-pin DIP)

Y1152A [1] Y1172A

(Y1159A)

87222C

87222D

87222E

87222R

4-port transfer

Low PIM Switch, 4-port transfer

DC – 26.5 GHz

DC – 40 GHz

DC – 50 GHz

DC- 26.5 GHz

5968-2216E

87222-80007

Included

24 VDC

Included 161

(16-pin DIP) Y1154A [2] Y1173A

(Y1158A)

Supported Keysight Switches

and Attenuators

The Keysight 34945A and L4445A

Microwave Switch/Attenuator Drivers and

the L4490A/L4491A RF Switch Platform

support virtually any RF/Microwave switch

or attenuator.

Table 1, shown on the following page, is

a list of commonly used and supported

Keysight switches and attenuators with

their recommended options. Use Table 1

to locate your switch(es)/attenuator(s) and

the accessories required. You may find it

necessary to refer to the table frequently

as you work through this guide.

Note that the switches, attenuators, and

accessories shown in Tables 1 and 2 are

not included with the instrumentation

and must be ordered separately! Use the

chart on page 13 to track your selections

as you determine your configuration.

03 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Switch

model Description

Frequency

range

Reference

document

number 1

Coil

voltage

option

Position

indicator

option

connector

option

Distribution board

[number of

switches/board]

Bracket kit 3

(Cable kit) 3

L7104A

L7104B

L7104C

L7106A

L7106B

L7106C

L7204A

L7204B

L7204C

L7206A

L7206B

L7206C

SP4T 4-port latching, terminated

SP6T 6-port latching, terminated

SP4T 4-port latching, un-terminated

SP6T 6-port latching, un-terminated

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

5989-6030EN

024 Included 161

(16-pin DIP) Y1151A [2] Y1172A

(Y1159A)

L7222C

4-port transfer latching, terminated

DC – 26.5 GHz 5989-6084EN Included Included 161

(16-pin DIP) Y1154A [2] Y1173A

(Y1158A)

8762A

8762B

8762C

8763A

8763B

8763C

8764A

8764B

8764C

8762F

Terminated latching 3-port (SPDT)

Terminated latching 4-port (transfer)

Terminated latching 5-port

75 ohms Terminated (SPDT)

DC – 4 GHz

DC – 18 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 18 GHz

DC – 26.5 GHz

DC – 4 GHz

DC – 18 GHz

DC – 26.5 GHz

DC – 4 GHz

5952-1873E

5964-3704E

024 N/A

8765A

8765B

8765C

8765D

8765F

Coaxial (SPDT),SMA

Coaxial (SPDT),3.5 mm

Coaxial (SPDT),2.4 mm

Coaxial (SPDT), 75 ohm, SMB

DC – 4 GHz

DC – 20 GHz

DC – 26.5 GHz

DC – 40 GHz

DC – 4 GHz

5952-2231E

5091-2679E

324 n/a

8766K

8767K

8768K

8769K

Coaxial (SP3T)

Coaxial (SP4T)

Coaxial (SP5T)

Coaxial (SP6T)

DC – 26.5 GHz

5959-7831

024 n/a 060

(12-pin Viking)

Y1155A [2]

Y1155A [1] Y1175A

8767M

8768M

8769M

Coaxial (SP4T)

Coaxial (SP5T)

Coaxial (SP6T)

DC – 50 GHz

5988-2477EN

024 n/a 10-pin DIP Y1153A [2] Y1175A

(Y1158A)

U9397A

U9397C

8 GHz Solid State

18 GHz Solid State

300 kHz-8 GHz

300 kHz–18

GHz

5989-6088EN

Included n/a Solder terminals Y1155A [8] Y1170A: L4491A

Y1171A: L4490A

Table 1. Common Keysight RF/Microwave Switches and Attenuators (continued)

04 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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1. Product and technical overviews for the

switches and attenuators listed can be

obtained by document number from the

Keysight RF & Microwave Test Accessories

web site. Go to http://www.keysight.com/

find/accessories, select ‘RF & Microwave Test

Accessories,’ and search for the document

number. Additional information can also

be found in the ‘RF and Microwave Test

Accessories Catalog’ accessible from this site.

If viewing this document on-line, click on the

reference document link.

2. Starting in June 2010, the current interrupt

function (formerly Option 403) is a standard

feature for these switches. The serial number

information below shows which switch units

have the current interrupt function included as

standard.

N1810UL:

Serial numbers MY07244672 and later

N1810TL:

Serial numbers MY07247927 and later

N1811TL:

Serial numbers MY07244660 and later

N1812UL:

Serial numbers MY07240668 and later

3. Bracket kits apply to the L4490A and L4491A.

These kits include pre-assembled control

cables and hardware for mounting switches/

attenuators to the brackets and the bracket

assemblies to the L4490A and L4491A RF

Switch Platforms. Each bracket kit supports

multiple switches (Table 2). The Cable-only

kits are primarily used with the 34945A and

L4445A, but can also be used with the L4490A

and L4491A. These cables must be assembled

and each kit contains material to build multiple

cables (Table 2).

4. Information on these attenuators plus

additional information on other attenuators

can be found in the latest version of the ‘RF

and Microwave Test Accessories Catalog.’

Table 1. Common Keysight RF/Microwave Switches and Attenuators (continued)

05 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Switch

model Description

Frequency

range

Reference

document

number 1

Coil

voltage

option

Position

indicator

option

connector

option

Distribution board

[number of

switches/board]

Bracket kit 3

(Cable kit) 3

84904K

84904L

84906K

84906L

84907K

84907L

11 dB max, 1 dB steps, 4 sections

90 dB max, 10 dB steps, 4 sections

70 dB max, 10 dB steps, 3 sections

DC – 26.5 GHz

DC – 40 GHz

DC – 26.5 GHz

DC – 40 GHz

DC – 26.5 GHz

DC – 40 GHz

5963-6944

24 V

(standard) Included

10-pin DIP

(standard) Y1153A [2]

Y1174A

(Y1158A)

84904M

84905M

84908M

11 dB max, 1 dB steps, 4 sections

60 dB max, 10 dB steps, 3 sections

65 dB max, 5 dB steps, 4 sections

DC – 50 GHz 5988-2475EN

024 Included

10-pin DIP

(standard) Y1153A [2]

Y1174A

(Y1158A)

8494G

8494H

8495G

8495H

8496G

8496H

8495K

8497K

11 dB max, 1 dB steps, 4 sections

70 dB max, 10 dB steps, 3 sections

110 dB max, 10 dB steps, 4 sections

70 dB max, 10 dB steps, 4 sections

90 dB max, 10 dB steps, 4 sections

DC – 4 GHz

DC – 18 GHz

DC – 4 GHz

DC – 18 GHz

DC – 4 GHz

DC – 18 GHz

DC – 26.5 GHz

24 V

(standard) Included

12-pin Viking

(standard) Y1153A [2] Y1175A

Step 2

Distribution Boards, Bracket

Kits, and Cable Kits

Switches and attenuators are connected

to the Keysight 34945A and L4445A

Microwave Switch/Attenuator Drivers and

the L4490A/L4491A RF Switch Platform

through distribution boards installed

on the 34945EXT module (see System

Interconnections Defined).

There are five distribution boards (Y1150A

– Y1154A) designed to allow Keysight’s

most popular switches and attenuators

to be driven directly. A sixth distribution

board, the Y1155A, is designed to drive

virtually any switch or attenuator by

providing screw terminals to connect to

relay coils and position indicators.

The distribution board required for each

switch/attenuator model and the number

of switches/attenuators supported per

board (shown in brackets [ ]) are listed in

Table 1.

The Y115x distribution boards are passive;

they only provide socket headers or screw

terminals that interface external devices

to the 34945EXT. The distribution boards

do provide access to position feedback

signals that can be used to drive LED’s

to visually represent a signal path, for

example.

Bracket and Cable Kit Usage

There are six bracket kits and three cable

kits available separately for switch/atten-

uator installation and control (Table 1). The

number of switches/attenuators supported

per kit is summarized in Table 2.

The bracket kits apply to the L4490A

and L4491A Each bracket kit contains

hardware for mounting the switch to the

bracket and for mounting the bracket

assembly in the chassis.

The cable-only kits are primarily used with

the 34945A and L4445A, but can also be

used with the L4490A and L4491A.

Figure 1. The Y1150A – Y1155A distribution boards

06 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Table 2. Bracket and Cable Kit Usage

Kit number Number of switches supported Control cable included Usage Notes

L4490A/L4491A Bracket Kits

Y1170A 5Yes L4491A Five brackets per kit. Cable is

pre-assembled.

Y1171A 5Yes L4490A Five brackets per kit. Cable is

pre-assembled.

Y1172A 5Yes L4490A

L4491A

Five brackets per kit. Cable is

pre-assembled.

Y1173A 6Yes L4490A

L4491A

Three brackets per kit. Two

switches per bracket. Cable is

pre-assembled.

Y1174A 5Yes L4490A

L4491A

Five brackets per kit. Cable is

pre-assembled.

Y1175A 5No L4490A

L4491A

Five brackets per kit. No cable

provided.

34945A/L4445A Cable Kits

Y1157A 4 —

34945A

L4445A

L4490A

L4491A

Cable only – must be assembled.

See Table 1 for applicable

switches and attenuators.

Y1158A 2 —

34945A

L4445A

L4490A

L4491A

Cable only – must be assembled.

See Table 1 for applicable

switches and attenuators.

Y1159A 2 —

34945A

L4445A

L4490A

L4491A

Cable only – must be assembled.

See Table 1 for applicable

switches and attenuators.

RF cable and connector

suppliers

There are several suppliers for RF cables

and connectors for the switches/attenua-

tors used within the L4490A and L4491A

RF switch platforms. For convenience,

three of these suppliers are listed below:

Pasternack Enterprises, Inc.

http://www.pasternack.com

Micro-Coax

http://www.micro-coax.com

S. M. Electronics L.L.C.

http://www.smelectronics.us

07 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Step 3

Switch/attenuator driver

instruments and platforms

For many applications, it is necessary

to locate the switching device as close as

possible to the DUT. Discrete switches and

attenuators are used for this purpose. Opti-

mum use of these devices requires switch/

attenuator drivers that are specifically

designed to provide the following features:

– Digital Outputs to drive relay coils

in either pulsed or continuous drive

mode,

– Digital Outputs that can drive switch

position feedback LEDs,

– Digital Inputs to sense the position of

the switches,

– Power distribution between the power

supply, switches, and control logic,

– Report generation that indicates how

often switches have been actuated.

These features are standard with the

Keysight 34945A and L4445A Microwave

Switch/Attenuator Drivers and the

L4490A/L4491A RF Switch Platform

The 34945A and L4445A

microwave switch/attenuator

drivers

For test systems requiring additional func-

tionality, consider the 34945A Microwave

Switch/Attenuator Driver module. The

34945A is a one-slot, plug-in module used

with the Keysight 34980A Multifunction

Switch/Measure Unit. The 34980A

Typical connections of these system

components are shown in Figure 2.

The L4490A/L4491A RF switch

platforms

Also for dedicated or stand-alone

RF/Microwave switching applications

are the Keysight L4490A and L4491A RF

Switch Platforms. The 2U L4490A

and 4U L4491A allow the mounting of

switches and attenuators within a chassis.

Included with the L4490A and L4491A at

shipment are:

Item Description

5061-0701 LAN cross-over cable for

direct PC to L4490A/L4491A

connection.

L4490-61603 9-pin D-SUB extension cable

for supplying +24 V to the

34945EXT module.

34945EXT Extender module

(included in the L4490A and

L4491A chassis).

The internal configuration and typical

system connections are shown in Figure 3.

offers a 6.5 digit DMM, and supports a

host of switching and control modules.

LAN, GPIB, and USB interfaces plus a

full-feature front panel are standard with

the 34980A.

For dedicated or stand-alone RF/

Microwave switching applications,

there is the L4445A Microwave Switch/

Attenuator Driver instrument. The L4445A

is a 1U, ½-rack LXI (LAN eXtensions for

Instrumentation) version of the 34945A.

LXI is an instrumentation standard for

devices that use the Ethernet (LAN) as

their primary communications interface.

The 1U, ½-rack reference refers to the

L4445A’s physical size relative to standard

EIA rack cabinet dimensions.

Understanding what is included when

the 34945A or L4445A is ordered and

those accessories which must be ordered

separately, simplifies the configuration

process.

The following items are included with the

34945A and L4445A at shipment:

Item Description

5061-0701 LAN cross-over cable for

direct PC to 34945A/L4445A

connection.

8121-1289* 9-pin D-SUB extension cable

for supplying +24 V to the

34945EXT module.

34945EXT Extender module

(one is automatically added

to each 34945A and L4445A

ordered.)

8121-1339 CAT-5E RJ45 cable

(included with the 34945EXT

for communication between

extender modules).

*Not available from Keysight. Can be purchased locally or from the vendor L-COM

(http://www.l-com.com) as part number CRMN9MF-10.

08 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Figure 2. 34945A and L4445A external connections

C O NT RO L BU S

A g ile n t T e c h no lo g ie s

L4445A

M ic ro w a v e S w itc h/A t te n u a to r D r iv e r

LA N

Re s et

A T TN

LA N

P W R

4321

E X P A N S IO N B U S

P O R T 2

P O R T 1

N O T E T HE R N E T

S E E M A N U A L !

E X T E R N AL

P O W E R IN P P U T

30 V D C M A X

I/ O A C C E S S

4321

E X P A N S IO N B U S

P O R T 2

P O R T 1

N O T E T HE R N E T

S E E M A N U A L !

E X T E R N AL

P O W E R IN P P U T

30 V D C M A X

I/ O A C C E S S

34945A Plug-in module

Keysight 34980A

LAN

hub/switch

* = standard LAN cables

LAN cross-over cables for direct

PC – 34980A/L4445A connection

if PC is non Auto-MDIX

(cable p/n 5061-0701)

Master 34945EXT connects to 1st slave

through Expansion Port 1. Expansion ports

on slaves are interchangesable.

Up to eight 34945EXT modules including the master per 34945A or L4445A

8121-1339

8121-1289

+24 V

Keysight L4445A

I/O interfaces:

LAN

GPIB (optional)

34945EXT #1

(master)

34945EXT #2

(1st slave) Ext power

24V/12V/5V

I/O interfaces:

LAN (shown)

GPIB

USB

*or

09 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Figure 3. L4490A and L4491A internal configuration and typical connections

Keysight L4491A

LAN

hub/switch

Cable p/n 5061-0701

* = standard LAN cables

LAN cross-over cables for direct PC –

L4490A/L4491A connection if PC is non Auto-MDIX

Master 34945EXT connects to 1st slave

through Expansion Port 1. Expansion ports

on slaves are interchangeable.

External power supply required for all slave

34945EXT modules EXTERNAL to the L4490A/L4491A.

EXTERNAL

POWER INPUT

30 VDC MAX

Up to seven slave 34945EXT modules per L4490A or L4491A

+24 V supplied

from L4491A

+24 V supplied

from L4491A

+24 V supplied

from L4490A

34945EXT #1

(master)

Keysight L4490A

34945EXT #1

(master)

L4491A Option 002

34945EXT #2

1st slave

I/O interfaces:

LAN

GPIB (optional)

10 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Numbering schemes

The channel numbers associated with

each bank on the 34945EXT are shown in

the following chart. The channel syntax

for the 34980A (34945A), L4445A, and

L4490A/L4491A is also shown.

Bank Channels

(lower)

Channels

(upper)

Bank 1 01 – 08 11 – 18

Bank 2 21 – 28 31 – 38

Bank 3 41 – 48 51 – 58

Bank 4 61 – 68 71 – 78

– 34945A

- slot #: 1-8 (34980A)

- ext # : 1-8 (34945EXT)

- ch #: see chart

– L4445A

<1> <ext #> <ch #>

- ext # : 1-8 (34945EXT)

- ch #: see chart

– L4490A/L4491A

<1> <ext #> <ch #>

- ext # : 1-8 (34945EXT)

- ch #: see chart

34945EXT modules are numbered ac-

cording to their position in the daisy-chain

sequence relative to the master 34945EXT

which is ext # 1.

System diagnostics

Often the most common problems with

switches/attenuators connected to the

34945EXT through distribution boards

are related to the switch and attenuator

cables. A seventh distribution board, the

Y1156A Verification Board, is used to

provide visual confirmation of the signal

path from the PC to distribution board

banks 1–4. Verifying the path from the PC

to a selected bank helps isolate suspected

problems in the entire path from PC to

switch.

Many Keysight switches contain position

indicator options that allow for electronic

verification of the switch position. The

34945EXT contains circuitry to detect

these signals, and the Y1156A diagnostic

board can also be used to test the

functioning of this circuitry.

System Interconnections

Defined

The following sections describe the

interconnections and components of the

34945A, L4445A, and L4490A/L4491A as

shown in Figures 2 and 3.

PC to 34945A, L4445A, or

L4490A/L4491A

When connecting the PC directly to the

34980A (34945A), L4445A, or L4490A/

L4491A, the LAN cross-over cable (p/n

5061-0701) provided with the instruments

is used. If your PC supports Auto-MDIX

or contains a LAN card with Gigabit data

transfer rates, the cross-over cable is not

required. A standard LAN cable may be

used instead. For network configurations

that include a LAN switch or router

between the PC and the instruments,

standard LAN cables are used.

Connections from the PC to the 34980A

(34945A) are also available through the

34980A GPIB and USB ports. Connection

via the optional GPIB interface is also

available for the L4445A and L4490A/

L4491A. However, access to the instru-

ment Web interfaces is only available

through the LAN connection (see the

product user’s guide).

34945A, L4445A, or

L4490A/L4491A to 34945EXT

As described in Step 2, Microwave

switches/attenuators are connected to the

34945A, L4445A, and L4490A/L4491A

through distribution boards (Y1150A

– Y1155A) installed on the 34945EXT

module. The 34945EXT is divided into four

banks (1–4) organized by channel number.

Any distribution board may be installed in

any bank, and multiple distribution boards

of the same type may be installed on the

same 34945EXT module.

Each 34945A or L4445A configuration

must contain at least one 34945EXT

module (a “master”) with limits on the

configuration as follows:

– Up to eight 34945EXT modules

allowed per 34980A mainframe which

can consist of eight 34945A modules

each with one 34945EXT module,

a single 34945A module with up to

eight 34945EXT modules, or any

combination in between,

– Up to eight 34945EXT modules

allowed per L4445A.

The 34945A and L4445A are connected

to the master 34945EXT using the 9-pin

D-Sub extension cable (8121-1289)

through which +24 V is also supplied.

A (master) 34945EXT module is built into

the L4490A and L4491A chassis. Up to

seven 34945EXT modules (in addition to

the master) are allowed per L4490A and

L4491A. A second 34945EXT module

(the first slave) is available in the L4491A

chassis as Option 002.

34945EXT to 34945EXT

Multiple (slave) 34945EXT modules are

connected through the expansion bus

ports using standard (i.e. non cross-over)

LAN cables. A LAN cable (p/n 8121-1339)

is included with each 34945EXT for this

purpose. The master EXT module must be

connected to the first slave module via the

(master’s) Expansion Bus Port 1, and either

Port 1 or Port 2 of the slave EXT module.

The expansion ports on the slave modules

are interchangeable.

34945EXT to external

power supplies

All slave 34945EXT modules and those

external to the L4490A or L4491A chassis

must use an external power supply or

supplies. The 34945EXT can only support

one external voltage level (+24 V, +12V, +5

V) at a time which applies to all distribu-

tion board banks on the 34945EXT. An

external supply can also be used with the

master 34945EXT.

11 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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L4490A and L4491A RF switch

platform product options

There are five product options

available for the L4491A and one

option available for the L4490A. All

options are factory installed and must

be specified at the time of order. The

product options include:

L4491A

–Option 001: multiport front panel.

Front panel modification for

mounting up to eight multiport

switches. Includes mounting

hardware. Switch cables must be

ordered separately

(Y1159A – Table 1).

–Option 002: Adds an additional

34945EXT module internal to the

L4491A chassis (Figure 3).

–Option 004: Adds 16-bit digital IO

and 28 bits of relay drive lines.

–Option 005: switch mounting – bays

(default option)

–Option 006: switch mounting –

bottom tray

L4490A

–Option 004: Adds 16-bit digital IO

and 28 bits of relay drive lines.

L4490A/L4491A bracket

layout guidelines

Switches installed in the L4490A

platform or in the L4491A platform

with Option 006 can be mounted in any

orientation that optimizes or simplifies

switch or attenuator wiring.

For the L4491A with default

Option 005, switches and attenuators

may be mounted in any of the “bays” and

in any combination. Figure 5 shows the

typical number of given brackets (Y1170A

– Y1175A) that can be installed in a bay.

Figure 5. L4491A mounting brackets per bay

Figure 4. L4490A/L4491A product option locations

12 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Internal/External Power

Supply Considerations

As shown in Figures 2 and 3, the channel

drive source for the master 34945EXT

is provided through the internal +24 V

power supply of the 34945A, L4445A, and

L4490A/L4491A. If necessary, external

supplies can be used. For either case, the

supply must meet the quiescent (continu-

ous) and switching current requirements of

the switches in your application.

Internal supply

When using the internal +24 V supply of

the 34945A or L4445A, the quiescent

current draw must not exceed 100 mA,

with a switching pulse current that does

not exceed 200 mA. The duration of the

switching pulse must be < 15 ms with a

25% duty cycle. The remainder of the duty

cycle (75%) allows recovery time for the

supply to provide the next pulse.

For the L4490A/L4491A, the quiescent

and switching currents from the supply

must not exceed the supply’s specification

of 600 mA continuous.

When current limits are exceeded,

overcurrent conditions can occur which

shuts down the internal supply. When this

happens, you must remove the device/

condition causing the overcurrent and

reset or cycle power on the instrument.

The quiescent current requirement of the

34945EXTs themselves is accounted for

by the internal supply rating and is not

included in quiescent current and switching

current calculations. Only the specified

currents (quiescent, switching) of the switch

must be considered.

As an example, the Keysight 87104/87106A,

B, C coaxial switches specify the following:

Supply current (switching: pulse width = 15 ms:Vcc = 24 VDC): 200 mA Nom

Supply current (quiescent): 50 mA Max

Using the internal +24 V supply, the current

required for actuating a 87104/87106

switch is:

[87104/87106 quiescent current] + [87104/87106 switching current]

[50 mA] + [200 mA]

= 250 mA (15 ms pulse, 50 mA quiescent)

The number of switches available and their

varying power requirements often make

it difficult to determine if the capacity of

the 34945A, L4445A, or L4490A/L4491A

internal +24 V supply will be exceeded. If

overcurrent conditions occur repeatedly

the use of an external power supply may be

required. Refer to the product user manuals

for more information.

13 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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External supply

Each 34945EXT module is limited to 2 A

continuous current from an externally

connected power supply (4.75 V to 30 V).

The actual amount of power required by

each EXT module depends on the types of

switches used.

When using an external power supply

with either the master 34945EXT module

or slave 34945EXT modules (required),

the supply must be able to provide the

quiescent current requirement of the EXT

modules, plus the quiescent and switching

currents of the switches themselves.

The power requirement of the 34945EXT

is 1.2 W. For supported external supply

voltages of 24 V, 12 V, and 5 V, the current

required for a single EXT module is as

follows:

current = power / voltage

24 V: 1.2 W / 24 V = 50 mA

12 V: 1.2 W / 12 V = 100 mA

5 V: 1.2 W / 5 V = 240 mA

If multiple 34945EXT modules are driven

by a single external supply, the power

required from the supply increases by

1.2 W for each EXT module present. Thus,

if two EXT modules are driven by a single

supply, the power value in the equations

becomes 2.4 W – doubling the current

requirement.

Remember that the external supply must

also meet the quiescent and switching

current requirements of the switch. Using

the Keysight 87104/87106A, B, C coaxial

switches from the internal supply example,

the switch specifications again are:

Supply current (switching: pulse width =15 ms:Vcc = 24 VDC): 200 mA Nom

Supply current (quiescent): 50 mA Max

The quiescent current required for the

34945EXT module is:

[34945EXT quiescent current from 24 V]

[24 V: 1.2 W / 24 V = 50 mA]

Therefore, the current required from an

external supply for actuating a single

87104/87106 switch on a single 34945EXT

module is:

[34945EXT quiescent current from 24 V] + [switch quiescent current] + [switching current]

[24 V: 1.2 W / 24 V = 50 mA] + [50 mA] + [200 mA]

= 300 mA (15 ms pulse, 100 mA quiescent)

In summary, when using an external

supply, the current calculations must

include the quiescent current requirement

of the 34945EXT and the quiescent

current requirement of each switch. These

quantities are then added to the switching

(pulse) current requirement of the device.

14 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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Data sheets

Keysight 34980A Multifunction Switch/

Measure Unit

5989-1437EN

http://cp.literature.keysight.com/litweb/

pdf/5989-1437EN.pdf

Keysight L4445A Microwave/Attenuator

Switch Driver

5989-4828EN

http://cp.literature.keysight.com/litweb/

pdf/5989-4828EN.pdf

Keysight L4490A/L4491A RF Switch

Platform

5989-7857EN

http://cp.literature.Keysight.com/ litweb/

pdf/5989-7857EN.pdf

Application notes

Test System Signal Switching

5988-8627EN

http://cp.literature.keysight.com/litweb/

pdf/5988-8627EN.pdf

Benefits of a Switch/Measure Unit

for Data Acquisition and Electronic

Functional Test

5989-1481EN

http://cp.literature.keysight.com/litweb/

pdf/5989-1481EN.pdf•

34980A Multifunction Switch/Measure-

System Modules Applications that benefit

from specific module features/functions

5989-2371EN

http://cp.literature.Keysight.com/ litweb/

pdf/5989-2371EN.pdf

For additional information please visit:

http://www.keysight.com/find/34980A

http://www.keysight.com/find/L4445A

http://www.keysight.com/find/L449xA

http://www.keysight.com/find/L4490A

http://www.keysight.com/find/L4491A

Related Keysight Literature

15 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

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16 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide

For more information on Keysight

Technologies’ products, applications or

services, please contact your local Keysight

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ISO9001 Quality Management System

www.keysight.com/go/quality

Keysight Technologies, Inc.

DEKRA Certified ISO 9001:2015

Quality Management System

This information is subject to change without notice.

Published in USA, January 19, 2018

5989-2272EN

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Keysight Technologies L4445A Configuration manual

Keysight Technologies L4445A Configuration manual

Keysight Technologies L4445A Configuration manual

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